The present invention is a tool for securing the head of a bolt in place while the nut on the bolt opposite the head is loosened or tightened.
It has long been well known to secure or attach two members by means of a bolt comprising a head, a threaded bolt shaft and a threaded nut operating on the shaft oppositely of the head. The shaft is placed through aligned holes in the two members and the nut is tightened to the point that the members (hereinafter the "work") are held securely together between the head and the nut. In many applications, the head extends outwardly of the work such that the head can be held against rotation by means of pliers, a wrench, or some similar tool while the nut is loosened or tightened.
In other applications, however, it is desirable that the head of the bolt be flush with the surface of the work. In such applications, the head is often shaped to be received and secured in a correspondingly shaped recess in the work and is thereby held against rotation while the nut is loosened or tightened. A common agricultural application for such bolts is in attaching a cultivator tooth (often referred to as "sweep") to a tine. This arrangement is satisfactory only so long as the head can be maintained in the recess. If the head is displaced from the recess due to longitudinal force applied to the bolt while the nut is loosened or tightened, the bolt will simply rotate with the rotation of the nut thereby frustrating loosening or tightening of the nut. Such "backout" is most often a problem when the space between the head and the nut is sufficient to permit the head to be fully withdrawn from the recess.
In some instances, this limitation can be overcome simply by the user applying manual pressure against the head while the nut is being turned. In many instances, however, the simultaneous application of manual pressure against backout is impossible, inconvenient or inadequate. For instance, in many situations where the nut may have rusted on the bolt shaft, the user often needs both hands in order to loosen the nut, and it is difficult to prevent backout.
It is one object of the present invention to prevent backout of the head of a bolt while the nut is loosened or tightened.
It is another object of the present invention to provide a tool for preventing backout of a bolt while being loosened or tightened which is lockable on the work to free both hands of the user.
To those ends, the tool comprises opposed handle members joined at a pivot, each of the handle members having a jaw member attached oppositely of the pivot such that as the handle members are moved more closely together (or closed), the jaw members will also close. The tool is lockable by virtue of an adjustable locking mechanism generally similar to the mechanism on lockable pliers sold under the trade name "Visegrip" whereby the tool may be adjusted to lock on differently sized work.
The first jaw member comprises a single, centrally positioned member which bears against the head of the bolt when the tool is in place. The second jaw member is generally U-shaped and comprises a pair of spaced members that are offset sidewardly with respect to the centerline of the tool for gripping the work oppositely of the first jaw member. When the tool is in place, the first jaw member acts against the head of the bolt to prevent backout, and the second jaw members are spaced from the nut to allow access to the nut for turning.